The Debian Project is an association of individuals who have made common cause to create a free operating system.

Debian GNU/Linux is:

• Full featured: Users can select which packages to install; Debian provides a tool for this purpose. You can find a list and descriptions of the packages currently available in Debian at any of the Debian mirror sites.
• Free to use and redistribute: There is no consortium membership or payment required to participate in its distribution and development. All packages that are formally part of Debian GNU/Linux are free to redistribute, usually under terms specified by the GNU General Public License.
• The Debian FTP archives also carry approximately 696 software packages (in the non-free and contrib sections), which are distributable under specific terms included with each package.
• Dynamic: With about 1033 volunteers constantly contributing new and improved code, Debian is evolving rapidly. The FTP archives are updated twice every day.

Although Debian GNU/Linux itself is free software, it is a base upon which value-added Linux distributions can be built. By providing a reliable, full-featured base system, Debian provides Linux users with increased compatibility, and allows creators to eliminate duplication of effort and focus on the things that make their distribution special.

A large part of the basic tools that fill out the operating system come from the GNU project; hence the names: GNU/Linux, GNU/kFreeBSD, and GNU/Hurd. These tools are also free.

Debian comes with over 51,000 packages, a package manager (APT), and other utilities that make it possible to manage thousands of packages on thousands of computers as easily as installing a single application. All of it free.

It's a bit like a tower. At the base is the kernel. On top of that are all the basic tools. Next is all the software that you run on the computer. At the top of the tower is Debian — carefully organizing and fitting everything so it all works together.